Conventionally, analog copiers were known. Recently, digital copiers that process digitized image data have appeared in the market. Further, digital multifunction machines that can perform the functions of a facsimile, a printer, and a scanner in addition to the functions of the digital copier have also come in the market.
FIG. 10 is a block diagram showing a hardware configuration of a conventional digital multifunction machine. This conventional digital multifunction machine is formed with different blocks as follows. One of the blocks comprises a series of components such as a scanning unit 1001, an image processing unit 1002, a video control section 1003, and a writing unit 1004. Another block constitutes a copier (copier block) formed with a memory control unit 1005 and a memory module 1006. The rest of the blocks comprises additional external application units, that is, a facsimile control unit 1012, a printer control unit 1013, and a scanner control unit 1014 connected to the other sections via a motherboard 1011. Based on this configuration, the functions as a digital multifunction machine have been performed.
The scanning unit 1001 scans an image to be converted to electric signals and outputs the signals to the image processing unit 1002. The writing unit 1004 reproduces the digital image signals from the video control section 1003 onto transfer paper as a reproduction image. The image processing unit 1002 performs processing for image quality such as correction to a degraded image and reproduction of gradation based on area gradation on the image data scanned by the scanning unit 1001.
The video control section 1003 performs controls for the bus. More specifically, the video control section 1003 controls input signals from the image processing unit 1002, output signals to the writing unit 1004, input/output signals to/from the memory control unit 1005, and input/output signals to/from the external application unit via the motherboard 1011.
The external application unit is connected to the other sections via the motherboard 1011, each of the application units functions as a discrete unit, and each unit has its own CPU and memory.
That is, in the copier block which performs the functions as a copier, a sequence of operations of the components such as the scanning unit 1001, the image processing unit 1002, the video control section 1003, and the writing unit 1004 are controlled by a system controller 1007, RAM 1008, and ROM 1009. While each of the units such as the facsimile control unit 1012, the printer control unit 1013, and the scanner control unit 1014 performs its functions by utilizing a part of the sequence of the operations established in the copier.
As a copier, for example, a job, that utilizes the memory module 1006 for image rotation and so on, is performed by storing image data in the memory module 1006 through the video control section 1003 and the memory control unit 1005 from the image processing unit 1002, performing the processing for image rotation, and reproducing the image via the video control section 1003 and the writing unit 1004. The sequence of these controls are performed in the system controller 1007.
On the other hand, the processing for bitmapping an image to be printed out in the printer control unit 1013 is not executed by the system controller 1007 and the memory control unit 1005, but CPU and memory, not shown, specifically provided in the printer control unit 1013 are used for the processing.
In other words, the functions of the digital multifunction machine are performed by adding the facsimile control unit 1012, the printer control unit 1013, and the scanner control unit 1014 on to the copier block established as one system with the series of components. This is based on the background that importance is placed on a processing speed, that is, the processing should be speeded up by forming the series of components with hardware such as ASIC (Application Specific Integrated Circuit).
Further, there is know an image processor (e.g., see Japanese patent application laid open HEI 08-274986A) which optimizes image processing of scanned signals, storage of images to memory, parallel operation of a plurality of functions, and image processing of the respective operations. This is one of the apparatuses in which the various types of image processing can be executed by one configuration for image processing.
Thus, the copier block has been established as one system in the conventional digital multifunction machine. Therefore, each of the units connected to the copier block such as the facsimile control unit 1012, the printer control unit 1013, and the scanner control unit 1014 has to construct its own system separately from the copier block in order to perform each of their functions.
Accordingly, a memory module, a control module, and a memory control module required for performing the functions of each of the units need to be provided in each of the units.
Therefore, the units can not make effective use of the memory module 1006 provided in the copier block, but also provision of plural memory modules for the respective units has led to increased size as an overall apparatus and also increased cost.
When a conflict occurs between a request for processing from the add-on facsimile control unit 1012 or printer control unit 1013 and a request for processing from the scanning unit 1001, the system controller 1007, that has been designed around a copying function section, controls the overall apparatus, therefore, the most appropriate image processing as the overall apparatus can not always be performed.
For example, once facsimile reception is started in the facsimile control unit 1012, the copy of a document can not be obtained until the facsimile reception is finished even if a few sheets of document are to be copied. That is, in the conventional art, a control mechanism that optimizes performance as an overall system and integrally controls the units has been missing.
Likewise, since the copier block has been established as one system, the functions of the copier block can not efficiently be improved in association with improved performance of peripheral units. For example, when only the scanning unit 1001 or the writing unit 1004 is altered, more specifically, when 400 dpi provided in the scanning unit 1001 or the writing unit 1004 is to be altered to 600 dpi, the functions of the overall apparatus have not easily been improved by the work only to replace the unit.
That is, a series of systems as the overall copier block have already been established so as to scan or write data by 400 dpi. Therefore, when the unit is to be replaced, a matrix size and threshold values or the like for intermediate processing are required to be changed. With regard to the other units, their setting contents may also be changed so as to enable scanning or writing of data by 600 dpi.
Accordingly, when the system is configured with the hardware such as ASIC, the hardware itself (custom-built IC and LSI) has to be replaced. Therefore, it is impossible to easily improve the functions of the overall apparatus in association with improved performance of the peripheral units only by replacing the peripheral units.
These problems may come up not only in the case of peripheral units but also in the case where improvement in functions such as operability of the digital multifunction machine is intended. That is, in order to improve functions of the digital multifunction machine, the work such that alteration has to be performed over the whole contents of the system is required. Therefore, it is quite impossible for designers to improve the functions of the digital multifunction machine in a simple manner. Further, the latest algorithm cannot easily be provided to users to utilize the digital multifunction machine.
Further, since the sections forming the copier are established as one system, when the digital multifunction machine is made use of as a scanner or a printer as a single unit, the functions can not easily be separated from each other.
As explained above, in the conventional digital multifunction machine, there has been such a problem that the most appropriate control mechanism is not constructed in the following point of making effective use of resources in the system such as sharing of the module, improvement of the function by replacement for each unit, and division of the function into a plurality of functions. Especially, there has been desired an image processor in which controls provided for input/output of data in/from image memory, that is most frequently used in the digital multifunction machine, are well linked to controls provided for the units.